Hydraulic Cylinder Overflow Seal for End-Position Pressure Equalization
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Solution Overview
Problem
Existing double-acting hydraulic working cylinders face challenges in achieving a definable pressure medium overflow between working chambers, particularly in end positions, due to design-related complexity and limited cross-sectional area for overflow, leading to operational reliability issues and wear.
Innovation Solution
The working cylinder design incorporates a seal with axial movement clearance and a piston ring with a defined gap, combined with recesses in the cylinder tube, to create a controlled overflow cross-section, allowing for precise pressure medium overflow in definable positions, thus enhancing operational reliability and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If valve arrangements with tappets are used to enable pressure medium overflow in end positions, then pressure equalization can be achieved, but the device complexity increases and the available installation space in the piston is reduced
Solution Approach 1:
The invention extracts the overflow function from complex valve arrangements and implements it through a simple axial movement of the seal along the piston rod, eliminating the need for tappets, valve bodies, and spring mechanisms while maintaining pressure equalization capability
Solution Approach 2:
Instead of using active valve components to create overflow passages, the invention uses the passive axial displacement of the seal itself to define the overflow cross-section, inverting the traditional approach from active valve control to passive seal positioning
2Reliability
If traditional valve arrangements are used for pressure medium overflow, then pressure equalization is possible, but the cross section for overflow is limited and design complexity increases
Solution Approach 1:
The overflow cross-section is made dynamic through the axial movement of the seal along the piston rod, allowing the cross-sectional area to vary with piston position and enabling larger overflow areas at end positions where pressure equalization is most needed
3Reliability
If spring-loaded valve bodies are used in the piston, then pressure medium can overflow between working chambers, but the installation space available for valve components is limited
Solution Approach 1:
The invention removes all valve components (spring-loaded valve bodies, tappets, closure parts) from the piston and implements pressure medium overflow through the axial movement of the seal along the piston rod, dramatically reducing the installation space required
Solution Approach 2:
The seal serves multiple functions: it prevents pressure medium leakage between working chambers during normal operation and simultaneously creates the overflow cross-section when axially displaced, eliminating the need for separate valve components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures a reliable and low-wear pressure medium overflow system, preventing abrupt pressure increases and reducing shear stresses and friction, thereby minimizing the risk of the 'diesel effect' and ensuring all cylinders reach their end positions.
Implementation Method 1
the seal (11) in the first inner ring groove (10) has an axial movement clearance... create a controlled overflow cross-section... allowing for precise pressure medium overflow
Implementation Method 2
a piston ring with a defined gap, combined with recesses in the cylinder tube, to create a controlled overflow cross-section... reducing shear stresses and friction
Data Source
AI summary
A working cylinder with pressure medium overflow. A piston has a first inner annular groove with a seal and a second inner annular groove with a piston ring that has a ring gap. The seal has an axial motion clearance. A tube inner wall has a recess axially disposed such that when the piston is at a first closure part, the recess is positioned opposite the seal. The working cylinder has an overflow and a lifting operating state. In the overflow operating state, the piston is in an end position at the first closure part with the seal is positioned, in an end clearance position of the axial movement clearance thereof and an overflow cross-section between a radial limit of the seal and the recess is open and an overflow channel is open. In the lifting operating state, the seal is positioned, in a proximal end clearance position opposite and the overflow cross-section and channel are closed.